The present invention relates to remotely operated tooling, and more particularly, to apparatus for remotely gripping and pulling a tube through the tube sheet of a nuclear steam generator.
Nuclear steam generators are massive heat exchangers in which thousands of tubes are supported within a large pressure vessel such that primary water at high temperature and pressure, passes through the tubes and thereby transfers heat to the secondary water outside the tubes, which is transformed into steam. The tubes are supported at their open ends in a thick plate, or tube sheet, at the lower head or bowl of the steam generator vessel.
For reasons that are well known in the field of nuclear steam generator servicing, the need sometimes arises to remove certain defective tubes from the steam generator. Because primary side water contains radioactive material which, over time, deposits in the tubes and in the lower head, direct human presence in the head to accomplish the tube removal should be minimised.